Currently, the available hardware technology for Medium Voltage (MV) power converters (>1000 v) drastically limits the switching frequency in comparison with the Low Voltage (LV) level, and thus, it degrades the power quality.
In order to optimize the power quality with minimum switching frequency and fulfill existing standards with MV power converters, the prior art suggests combining high order filters, multilevel converter technologies and Selective Harmonic Elimination-Pulse Width Modulation (SHE-PWM).
In particular the three level Neutral-Point-Clamped (3L-NPC) converter, where the three voltage levels are achieved by a DC bus divided into two capacitors connected in series, is considered to be a suitable topology for MV power converters.
While MV power conversion systems for open-loop applications are known, the electric industry increasingly demands MV power conversion systems for closed-loop applications.
This invention is addressed to the attention of that demand.